Crohn’s disease is a poorly understood inflammatory condition that affects the final part of the small intestine and the beginning section of the colon. It often causes bloody stools and malabsorption problems.

A high-animal-protein and high-fat diet (from foods other than fish) has been linked to Crohn’s disease in preliminary research.⁴ As with many other health conditions, it may be beneficial to eat less meat and dairy fat and more fruits and vegetables.

Some people with Crohn’s disease have food allergies and have been reported to do better when they avoid foods they are allergic to. One study found that people with Crohn’s are most likely to react to cereals, dairy, and yeast.⁵ Increasingly, baker’s yeast (found in bread and other bakery goods) has been implicated as a possible trigger for Crohn’s disease.⁶ Yeast and some cheeses are high in histamine, which is secreted during an allergenic response. People with Crohn’s disease lack the ability to break down histamine at a normal rate,⁷ so it is possible the link reported to yeast and dairy may not be coincidental.

In one trial, patients (rather than doctors) were asked which foods exacerbated Crohn’s symptoms.⁸ Those without ileostomies found nuts, raw fruit, and tomatoes to be most problematic, though responses varied from person to person, and other reports have come up with different lists.⁹ People with Crohn’s wishing to identify and avoid potential allergens should consult a doctor.

Nutritional supplements that may be helpful: Crohn’s disease often leads to malabsorption. As a result, inadequate levels of many nutrients are common. For this reason, it makes sense for people with Crohn’s disease to take a high potency multiple vitamin/mineral supplement. In particular, deficiencies in zinc, folic acid, vitamin B12, vitamin D and iron have been reported.^{11 12 13} Zinc, folic acid, and vitamin B12 are needed to repair intestinal cells damaged by Crohn’s disease. Some doctors recommend 25–50 mg of zinc (balanced with 2–4 mg of copper), 800 mcg of folic acid, and 800 mcg of vitamin B12. Iron status should be evaluated by a doctor before considering supplementation.

Vitamin A is needed for the growth and repair of cells that line both the small and large intestine.¹⁴ Reports have appeared of people with Crohn’s responding to vitamin A.^{15 16} However, in one trial of 86 people with Crohn’s who were in remission, vitamin A supplementation for fourteen months led to no benefit.¹⁷ Therefore, although some doctors recommend 50,000 IU per day for adults with Crohn’s disease, this approach remains unproven. An amount this high should never be taken without qualified guidance, nor should it be given to a woman who is or could become pregnant.

Vitamin D malabsorption is common in Crohn’s¹⁸ and can lead to a deficiency.¹⁹ Successful treatment with vitamin D for osteomalacia (bone brittleness caused by vitamin D deficiency) triggered by Crohn’s disease has been reported.²⁰ Another study found 1000 IU per day prevented bone loss in Crohn’s patients while an un-supplemented control group experienced significant bone loss.²¹ A doctor should evaluate vitamin D status and suggest the right level of vitamin D supplements.

Diarrhea caused by Crohn’s disease has partially responded to Saccharomyces boulardii supplementation in double-blind research.²⁷ Although the amount used in this trial—250 mg taken three times per day—was helpful, research successfully using Saccharomyces boulardii supplements with people suffering from other forms of diarrhea has used as much as 500 mg taken four times per day.²⁸

Individuals with Crohn’s disease may be deficient in pancreatic enzymes, including lipase.²⁹ In theory, supplemental enzymes might improve malabsorption associated with Crohn’s. People with Crohn’s disease considering supplementation with enzymes should consult a doctor.

Herbs that may be helpful: Doctors sometimes use a combination of herbs to soothe inflammation throughout the digestive tract. The formula contains marshmallow, slippery elm, cranesbill, and several other herbs. Marshmallow and slippery elm are mucilaginous plants that help soothe inflamed tissues. Cranesbill is an astringent. Clinical trials using this combination have not been conducted.

A variety of anti-inflammatory herbs have historically been recommended by doctors for people with Crohn’s disease. These include yarrow, chamomile, licorice, and aloe juice. Cathartic preparations of aloe should be avoided. No research has been conducted to validate the use of these herbs for Crohn’s disease.

Tannin-containing herbs may be helpful to decrease diarrhea during acute flare-ups and have been used for this purpose in traditional medicine. An uncontrolled study using isolated tannins in the course of usual drug therapy found them more effective for reducing diarrhea than no additional treatment.³⁰ Tannin-containing herbs of potential benefit include agrimony, green tea (also anti-inflammatory), oak, witch hazel, and cranesbill. Use of such herbs should be discontinued before the diarrhea is completely resolved, otherwise the disease could be exacerbated.

Information about the effects of a particular supplement or herb on a particular condition has been qualified in terms of the methodology or source of supporting data (for example: clinical, double blind, meta-analysis, or traditional use). For the convenience of the reader, the information in the table listing the supplements for particular conditions is also categorized. The criteria for the categorizations are: "Primary" indicates there are reliable and relatively consistent scientific data showing a health benefit. "Secondary" indicates there are conflicting, insufficient, or only preliminary studies suggesting a health benefit or that the health benefit is minimal. "Other" indicates that an herb is primarily supported by traditional use or that the herb or supplement has little scientific support and/or minimal proven health benefit.

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